A scanner scans pictures, texts, and photographs into graphic files.
FIG. 1A is a partially schematic diagram of a conventional scanner. As shown in
FIG. 1A, a conventional scanner includes a lamp 101 and an object 103 to be scanned. The lamp 101 emits a light beam toward the object 103. Specifically, the intensity of the light beam received by the object 103 must reach a certain level so that the object (e.g. a picture or a text) can be precisely converted into a graphic file. However, the light beam from the areas at two sides of the lamp is not very strong due to the physical constraint of the lamp 101 itself; therefore, the designer of the scanner has to employ a light tube that its length is longer than the widest width of the object to be scanned.
Also, referring to FIG. 1B, a conventional scanner includes a lamp 101, an object to be scanned 103, and a reflector 105. The reflector 105 is located above the lamp 101. When the lamp 101 emits a light beam, the object 103 will receive a direct light beam from the lamp 101 as well as a reflected light beam from the reflector 105.
In addition, as shown in FIG. 1C, the reflector 105 is a parabolic surface, and the lamp 101 is placed on the focus of the reflector 105. When the reflector 105 reflects the light beam emitted by the lamp 101, according to the property of the light beam, the reflected light beam will be emitted downwardly in parallel toward the object 103 so that the intensity of the light beam received by the object 103 can be intensified to increase the work performance of the scanner. However, the light beam at two sides of the light tube is insufficient due to the physical constraint of the lamp 101.
On the other hand, designing a slimmer and smaller apparatus has been a trend pursued by designers. However, the light beam in the boundary regions of the light tube hampers the space utilization of a scanner. For instance, in an A4 scanner, the length of its light tube is generally longer than the widest width of the object to be scanned in about 3 to 4 centimeters, which in turn makes it impossible for the dimension of the scanner to be diminished. Therefore, it is imperative to have a device that compensates the light intensity in the boundary regions of the lamp so as to reduce the dimension of the scanner.